#include <iostream>
#include <string>

using namespace std;

int add_func(int val_1, int val_2)
{
    return val_1 + val_2;
}

double add_func(double val_1, double val_2)
{
    return val_1 + val_2;
}

void add_func(double val_1, double val_2, double & val_3)
{
    val_3 = val_1 + val_2;
}

void add_func(string s1,double val_1, double val_2)
{
    cout << s1 << val_1 + val_2 << endl;
}

int main(int argc, char const *argv[])
{
    cout << "80 + 90 = " << add_func(80, 90) << endl;
    cout << "80.5 + 90.5 = " << add_func(80.5, 90.5) << endl;

    double val_3 ;
    add_func(80.5, 90.5, val_3);
    cout << "80.5 + 90.5 = " << val_3 << endl;

    add_func("80.5 + 90.5 = ", 80.5, 90.5);

    return 0;
}
